On the dynamical state of galaxy clusters: Insights from cosmological simulations - II

Weiguang Cui, Chris Power, Stefano Borgani, Alexander Knebe, Geraint F. Lewis, Giuseppe Murante, Gregory B. Poole

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Abstract

Using a suite of cosmology simulations of a sample of > 120 galaxy clusters with log (MDM, vir) ≤ 14.5. We compare clusters that form in purely dark matter (DM) run and their counterparts in hydro-runs and investigate four independent parameters that are normally used to classify dynamical state. We find that the virial ratio η in hydro-dynamical runs is ~10 per cent lower than in the DM run, and there is no clear separation between the relaxed and unrelaxed clusters for any parameter. Further, using the velocity dispersion deviation parameter ζ, which is defined as the ratio between cluster velocity dispersion σ and the theoretical prediction , we find that there is a linear correlation between the virial ratio η and this ζ parameter. We propose to use this ζ parameter, which can be easily derived from observed galaxy clusters, as a substitute of the η parameter to quantify the cluster dynamical state.

Original languageEnglish
Pages (from-to)2502-2510
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Volume464
Issue number2
DOIs
Publication statusPublished - 11 Jan 2017

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Cui, Weiguang ; Power, Chris ; Borgani, Stefano ; Knebe, Alexander ; Lewis, Geraint F. ; Murante, Giuseppe ; Poole, Gregory B. / On the dynamical state of galaxy clusters : Insights from cosmological simulations - II. In: Monthly Notices of the Royal Astronomical Society. 2017 ; Vol. 464, No. 2. pp. 2502-2510.
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On the dynamical state of galaxy clusters : Insights from cosmological simulations - II. / Cui, Weiguang; Power, Chris; Borgani, Stefano; Knebe, Alexander; Lewis, Geraint F.; Murante, Giuseppe; Poole, Gregory B.

In: Monthly Notices of the Royal Astronomical Society, Vol. 464, No. 2, 11.01.2017, p. 2502-2510.

Research output: Contribution to journalArticle

TY - JOUR

T1 - On the dynamical state of galaxy clusters

T2 - Insights from cosmological simulations - II

AU - Cui, Weiguang

AU - Power, Chris

AU - Borgani, Stefano

AU - Knebe, Alexander

AU - Lewis, Geraint F.

AU - Murante, Giuseppe

AU - Poole, Gregory B.

PY - 2017/1/11

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AB - Using a suite of cosmology simulations of a sample of > 120 galaxy clusters with log (MDM, vir) ≤ 14.5. We compare clusters that form in purely dark matter (DM) run and their counterparts in hydro-runs and investigate four independent parameters that are normally used to classify dynamical state. We find that the virial ratio η in hydro-dynamical runs is ~10 per cent lower than in the DM run, and there is no clear separation between the relaxed and unrelaxed clusters for any parameter. Further, using the velocity dispersion deviation parameter ζ, which is defined as the ratio between cluster velocity dispersion σ and the theoretical prediction , we find that there is a linear correlation between the virial ratio η and this ζ parameter. We propose to use this ζ parameter, which can be easily derived from observed galaxy clusters, as a substitute of the η parameter to quantify the cluster dynamical state.

KW - Cosmology: theory

KW - Galaxies: clusters: general

KW - Galaxies: evolution

KW - Galaxies: haloes

KW - Galaxies: kinematics and dynamics

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